Linear low density polyethylenes, and blends and articles made therefrom, are generally known in the art. Such polymers and polymer blends have typically been made from a linear low density polyethylene produced using a Ziegler-Natta catalyst in a gas phase process.
U.S. Pat. No. 6,255,426 describes polymers of ethylene and at least one α-olefin having at least five carbon atoms obtained by a continuous gas phase polymerization process using supported catalyst of an activated molecularly discreet catalyst such as a metallocene. The polymerization process is performed in the substantial absence of an aluminum alkyl-based scavenger, and results in a linear low density polyethylene having a combination of good shear thinning behavior and impact strength.
WO 2004/022646 A1 describes heat shrinkable monolayer and multilayer films having good optical and mechanical properties. The films are formed of a blend of a polyethylene copolymer and a second polymer, such as a low density polyethylene. In particular, monolayer and multilayer shrink films are described that include in at least one layer a metallocene-catalyzed polyethylene resin. Also described are articles wrapped with such films.
WO 2004/022634 A1 describes stretch films having at least one layer formed of or including a polyethylene copolymer having a draw ratio of at least 250%, a tensile stress at the natural draw ratio of at least 22 MPa, and a tensile stress at second yield of at least 12 MPa.
While many prior art documents describe processes and polymers using the same monomers as those described herein and similar processes to those described herein, none describe polymer blends and articles made from those polymer blends that combine good shear thinning, and therefore relatively favorable extrusion and other melt processing properties, with high stiffness and high impact strength.